Printed books have been in existence for hundreds of years. So-called electronic books are also known in the art and are increasingly becoming a part of ordinary life. In an electronic book, documents are presented to a reader using a computer-based display device. Examples of such devices are the “ROCKET EBOOK” device by NuvoMedia, Inc. and the “SOFTBOOK READER” device by Softbook Press, Inc. Some in the industry believe that electronic books will someday become a substitute for printed books. Given current trends, it appears that electronic books will, at the very least, become a common alternative to printed books in the near future.
The potential success of electronic books is largely dependent upon their ability to replicate the success of printed books as an information delivery system. It is important to recognize that printed books are, in fact, a system for delivering information. Printed books are effective in part because, when well crafted, they resonate with the human ability to visually recognize patterns. Typographers and printers have long understood that books work best as sources of information when a reader's processing of the printed words becomes essentially unconscious, leaving the reader's conscious cognitive processing available to more efficiently process content and meaning.
Stated another way, a well-formed book is one that allows a reader to become immersed in the author's content and imagery, without being conscious of the fact that they are actually reading a book.
To facilitate such immersive reading experiences, the form and formatting of printed documents becomes crucial. Well-formed printed matter depends upon the coordination of a variety of variables that individually seem trivial but, when combined for an overall effect, greatly influence a reader's ability to become immersed in reading. Examples of such variables include the type face and size, letter and word spacings, line length, size of margins, leading (i.e., the amount of space between printed lines), indentation, justification, hyphenation and language. Since the inception of printed matter, such variables, taken together as a complete system, have been refined and optimized. For example, Table 1 below illustrates one interpretation of cause and effect relationships between various formatting variables. In particular, Table 1 illustrates how changes to variables along the vertical axis have an effect (represented by boxes having a “yes” therein) on those variables along the horizontal axis.
TABLE 1FontFontLinePagina-T/BFaceSizeHeadingsIndentsLeadingLengthJustif.tionMarginsFontYesYesYesYesYes——YesYesFaceFont Size—YesYesYesYesYesYesYesYesHeadings—YesYesYesYesYes——Indents———Yes—YesYes——Rotation———Yes—Yes—YesYesFormYesYesYesYes—YesYesYesYesFactorHowever, to date, systems for displaying electronic documents have generally not adhered to the principle that formatting variables are interrelated. Ironically, many computer-based document authoring/displaying mechanisms have been more concerned with optimizing content for printed display, rather than electronic display, because, until recently, the electronic display of documents has not been viewed as an end itself but merely as a means to more effectively produce printed matter.
Additionally, the capability to quickly alter formatting variables in electronic documents has not necessarily improved the readability of electronic documents, and in many cases seriously detracts from readability. An example of this would be when a user resizes a typical Web browser so that it occupies the entire display of a desktop or laptop computer. In many Web document implementations, this immediately results in a line length for the main text of the document which is uncomfortable to read because it requires excessive head and eye movement to take in the full lines of text. That is, a problem with many platforms currently used to display electronic documents is that they allow certain formatting variables to be changed without necessarily optimizing the other formatting variables as a result. For example, in some word processing applications, one can increase or decrease the size of the font used. In response, the word processing software will increase the amount of leading. While this may be appropriate in some cases, it still ignores the typographic principle that other formatting variables should also be altered in light of the change to the font size in order to optimize readability of the document. Similar deficiencies exist in other platforms. For example, in the “ROCKET EBOOK” device, the capability exists to adjust font size between a large and small setting. However, changing this variable does not appear to result in the other formatting variables being changed to optimally cooperate with the new font size. The effect of this failure to optimize formatting variables is the likely degradation of the overall readability of the electronic document.
Some efforts have been made to address these shortcomings. For example, a system is disclosed in U.S. patent application Ser. No. 08/847,427 entitled METHOD AND SYSTEM FOR DYNAMICALLY ADAPTING THE LAYOUT OF A DOCUMENT TO AN OUTPUT DEVICE in which the particular display characteristics of a given display device are used to dictate, in part, the formatting of an electronic document. While the system disclosed in that patent application represents a significant advance in the art, a need exists for a system in which changes to one or more formatting variable result in the optimized modification of remaining formatting variables.